Cardiac Rhabdomyomas Presenting with Critical Cardiac Obstruction in Neonates and Infants: Treatment Strategies and Outcome, A Single-Center Experience.

Cardiac rhabdomyomas are the most common benign pediatric heart tumor in infancy, which are commonly associated with tuberous sclerosis complex (TSC). Most rhabdomyomas are asymptomatic and spontaneously regress over time. However, some cases especially in neonates or small infants can present with hemodynamic instability. Surgical resection of the tumor, which has been the gold standard in alleviating obstruction, is not always possible and may be associated with significant morbidity and mortality. Recently, mammalian target of rapamycin inhibitors (mTORi) have been shown to be safe and effective in the treatment of TSC. We present the outcomes of neonates and an infant who received treatment for symptomatic rhabdomyomas at a tertiary cardiology center. Medical records were reviewed to obtain clinical, demographic, and outcome data. Six patients received interventions for symptomatic rhabdomyomas, median age at presentation was 1 day old (range from 1 to 121 days old), and 67% of the patients had a pathogenic mutation in TSC gene. One patient underwent surgical resection of solitary tumor at right ventricular outflow tract (RVOT) successfully. In the four patients with left ventricular outflow tract (LVOT) obstruction, two patients received combined therapy of surgical debulking of LVOT tumor, Stage I palliation procedure, and mTORi and two patients received mTORi therapy. One patient with RVOT obstruction underwent ductal stenting and received synergistic mTORi. Four of the five patients had good response to mTORi demonstrated by the rapid regression of rhabdomyoma size. 83% of patients are still alive at their latest follow-up, at two to eight years of age. One patient died on day 17 post-LVOT tumor resection and Hybrid stage one due to failure of hemostasis, in the background of familial factor VII deficiency. Treatment of symptomatic rhabdomyoma requires individualized treatment strategy based on the underlying pathophysiology, with involvement of multidisciplinary teams. mTORi is effective and safe in inducing rapid regression of rhabdomyomas. A standardized mTORi prescription and monitoring guide will ensure medication safety in neonates and infants with symptomatic cardiac rhabdomyoma. Although the majority of tumors responded to mTORi, some prove to be resistant. Further studies are warranted, ideally involving multiple international centers with a larger number of patients.

Use of the Medtronic Microvascular Plug 7Q for transcatheter closure of large patent ductus arteriosus in infants weighing less than 2.5 kg.

BACKGROUND: The sole Food and Drug Administration-approved device for transcatheter closure of the patent arterial duct in premature infants is indicated for patent ductus arteriosus (PDAs) ≤ 4 mm in diameter. We report a two-center experience with transcatheter closure of large PDAs (>4 mm) in infants weighing <2.5 kg using the Microvascular Plug 7Q (MVP-7Q) device. METHODS: This is a retrospective review of departmental databases and medical charts to define patient cohort and report demographic, procedural, and follow-up data. RESULTS: Twenty-two patients (12 male) with a median gestational age and birthweight of 25.5 weeks (interquartile range [IQR] = 24-28) and 800 g (572-1075), respectively, underwent attempted PDA occlusion with the MVP-7Q using a transvenous approach. The median age and weight at the time of PDA occlusion was 32 days (IQR = 24-28) and 1100 g (IQR = 960-1700), respectively. The median PDA length was 12 mm (IQR = 11-12.65). The median PDA diameters at the aortic and pulmonary ends were 5.1 (IQR = 4.9-5.5) and 4.8 mm (IQR = 4.6-5.3), respectively. Successful device occlusion was achieved in 20 patients (91%). There were two failed attempts: One due to inappropriate sizing, and the other secondary to left pulmonary artery stenosis. There were no procedural complications and no residual shunting on follow-up. CONCLUSIONS: The MVP-7Q is safe and effective for transcatheter closure of large (>4 mm) PDAs in infants <2.5 kg. The lack of retention disks may help with avoiding impingement on surrounding vessels.

Transcarotid Approach to Ventricular Septal Defect Closure in Small Infants.

Perimembranous ventricular septal defect closure in small infants has traditionally been a surgically treated defect, although alternative hybrid strategies are emerging. We aim to describe a novel approach to retrograde device closure of clinically relevant perimembranous ventricular septal defects in small infants via carotid cutdown. A retrospective review of all patients managed with attempted carotid cutdown for device closure of a perimembranous ventricular septal defect was recorded at a single tertiary cardiac centre. We summarized data on successful device deployment, conversion to open repair, complications, and length of stay. Eighteen infants with median (IQR) age of 7 months (5-9 months) and weight of 7.1 kg (6.5-7.8 kg) with clinically relevant PMVSD underwent attempted retrograde closure via carotid cutdown. Median (IQR) defect size was 8 mm (7-9 mm). Successful device deployment without significant aortic or tricuspid valve interference occurred in 15 (83%) patients. Three patients were converted to open repair, one following damage to the tricuspid valve apparatus. Median (IQR) hospital stay was 1 day (1-3 days). There were no complications related to carotid cutdown. Retrograde device closure of hemodynamically significant PMVSD is feasible and effective in small infants. Decision to convert to surgical repair should be made early if suboptimal device placement occurs. Carotid evaluation should be performed to rule out any access-related complications.

Case series of late lead dislodgement of Medtronic SelectSecure 3830 pacing leads in growing paediatric patients.

BACKGROUND: The SelectSecure lumenless 3830 pacing lead is often considered to be the pacing lead of choice for transvenous pacing in children because of its small diameter, lead strength, and reliable long-term sensing and pacing characteristics. One of the potential long-term pitfalls of a sturdy pacing lead is relative retraction with growth in children resulting in late lead dislodgement. CASE SUMMARY: We report two cases of late SelectSecure 3830 lead dislodgement at 11.8 years (Case 1) and 8.8 years (Case 2), respectively, post the initial implantation. Case 1 was diagnosed with congenital complete heart block (CHB) at 9 months old when he presented with unconfirmed diphtheria infection. Case 2 was diagnosed with CHB at 14 weeks of age with positive maternal anti-Ro antibodies. Both patients underwent implantation of a transvenous permanent pacemaker implantation with Medtronic SelectSecure 3830 lead due to symptomatic bradycardia. Apart from a pulse generator change at 8.5 years (Case 1) and 7 years (Case 2), respectively, post-implant due to normal battery depletion, both patients are well in the interim. DISCUSSION: As part of the pacemaker follow-up for rapidly growing children, we recommend more frequent surveillance of lead 'tautness' by chest radiography especially in children with CHB with no underlying heart rhythm.

Hybrid Subxiphoid Perventricular Approach as an Alternative Access in Neonates and Small Children Undergoing Complex Congenital Heart Interventions.

The hybrid subxiphoid perventricular approach provides direct access through the heart and may alleviate the technical limitations of complex percutaneous interventions particularly in infants with low body weight. We present the outcomes from a tertiary cardiology center using this approach. We performed a retrospective review of all patients less than 15 kg who underwent a hybrid perventricular approach via a small subxiphoid incision. Medical records were reviewed to obtain clinical, demographic and outcome data. Seventeen patients underwent 18 hybrid perventricular procedures using a subxiphoid approach. Median age at time of procedure was 4.6 months (IQR = 1.6 to 18 months) and median weight was 6.2 kgs (IQR = 3.4 to 8.6 kgs). Six patients underwent hybrid pulmonary valve replacement (PVR), 5 patients underwent pulmonary outflow stenting, and 5 infants underwent hybrid ventricular septal defect (VSD) device closure. One patient with a single ventricle who did not tolerate a percutaneous approach underwent left pulmonary artery (LPA) stenting for severe LPA coarctation with subsequent right ventricular outflow tract (RVOT) stenting. One further patient underwent implantation of a larger diameter stent for pulmonary artery bifurcation stenosis. Procedure success rate was 89% with two of the VSD cases reverted to open surgical repair. There were no intra-procedural complications; however, one patient died within 72 h. Minor adverse events occurred in 2 patients including a wound infection in one patient with an immunodeficiency syndrome. Hybrid subxiphoid perventricular approach provides an excellent alternative access to the heart especially in low birth weight infants to prevent hemodynamic instability or in small children requiring large delivery sheaths.

Procedural technique for hybrid pulmonary valve replacement in infants and small children.

OBJECTIVES: Hybrid approach to pulmonary valve replacement (PVR) in the paediatric population has been reported, although data in infants and small children are limited. Several strategies are now possible. The aim of this study is to review our hybrid PVR strategy in a complex patient cohort, outlining a variety of approaches employed in our centre. METHODS: We performed a retrospective review of infants and small children who underwent hybrid PVR between May 2017 and April 2019 in a single tertiary cardiology centre. Medical records were reviewed to ascertain demographic, clinical and outcome data. RESULTS: Ten patients with a median (interquartile range) age of 1.5 years (1.1-1.9) and weight of 8.8 kg (8-10.6) were managed with hybrid pulmonary valve insertion. Eight patients had perventricular approach (4 sternotomy and 4 subxiphoid) and 2 patients had surgically sutured valve. Six patients underwent cardiopulmonary bypass for associated lesions. Three had insertion of the valve into conduits and 7 were deployed into native right ventricular outflow tracts. The pulmonary valve was successfully inserted in all 10 patients with no mortality. Postprocedural complications included paravalvar leak in 2 patients, suspected endocarditis in 1 patient who developed early valve regurgitation and wound infection in 1 patient. CONCLUSIONS: Several approaches to hybrid PVR may be employed in small children with a high success rate. Follow-up studies are required to evaluate longer term durability of these approaches compared to standard surgical replacement.

Near-field energy extraction with hyperbolic metamaterials.

Although blackbody radiation described by Planck's law is commonly regarded as the maximum of thermal radiation, thermal energy transfer in the near-field can exceed the blackbody limit due to the contribution from evanescent waves. Here, we demonstrate experimentally a broadband thermal energy extraction device based on hyperbolic metamaterials that can significantly enhance near-field thermal energy transfer. The thermal extractor made from hyperbolic metamaterials does not absorb or emit any radiation but serves as a transparent pipe guiding the radiative energy from the emitter. At the same gap between an emitter and an absorber, we observe that near-field thermal energy transfer with thermal extraction can be enhanced by around 1 order of magnitude, compared to the case without thermal extraction. The novel thermal extraction scheme has important practical implications in a variety of technologies, e.g., thermophotovoltaic energy conversion, radiative cooling, thermal infrared imaging, and heat assisted magnetic recording.

Familial distal foregut atresia in a family with likely autosomal dominant inheritance pattern.

Familial occurrence of distal foregut atresia (DFA) (Type 1) is rare. Diagnosis is based upon the clinical symptomatology and confirmed by radiological studies, surgery and histology. A number of reports have described families in which several family members have been involved and suggested an autosomal recessive mode of inheritance. Little is known about the underlying genetic causes or indeed the likely pathogenic mechanism. We report a family in which there are five affected cases including three siblings where the DFA appears to be inherited in an autosomal dominant inheritance pattern with reduced penetrance.

Broadening the phenotype associated with mutations in UPF3B: two further cases with renal dysplasia and variable developmental delay.

We present two brothers with mutations in UPF3B, an X-linked intellectual disability gene. Our family consists of two affected brothers and a carrier mother. Both affected brothers had renal dysplasia. A maternal uncle died from a congenital heart defect at 4 months. The two boys had variable degrees of developmental delay. One had macrocephaly, significant expressive speech delay and constipation. The other brother had normocephaly, obsessional tendencies and was diagnosed with high functioning autism. The phenotypically normal mother had 100% skewed X-inactivation. Our cases expand the phenotype seen with UPF3B mutations and highlight the variability within families.